Subject: Re: zeta Ori From: Alex Fullerton Date: 9/9/11 3:50 PM To: "Eric L. N. Jensen" , David Cohen , Marc Gagné CC: Maurice Leutenegger , Jon Sundqvist , Stan Owocki , Veronique Petit Hi All, Attached are several fragmentary time series of Halpha spectra, which will give a sense of the time scales and amplitudes associated with the prominent near-star "wind" variability of Zeta Ori = HD 37742. These were taken at a variety of observatories by Lex Kaper and me in the mid-to late 90's, and have been gathering dust for a while. In each panel, time progresses from top to bottom. The mid-point of the integration time are indicated along the right-hand side in days. The rms amplitude of the variation as a function of wavelength (TVS = temporal variance spectrum) is shown in the bottom panel. See also Fig. 1 of Morel et al. http://adsabs.harvard.edu/abs/2004MNRAS.351..552M This is the source of the standard wisdom that the rotation period of Zeta Ori is ~7 days, which is not really supported by the attached observations, in particular bythe OHP96 data set. There's an impressive "random" component evident in the ESO97 data set. Cheers, Alex On 9/9/11 2:39 PM, "Eric L. N. Jensen" wrote: > >I definitely plan to spend some time in the second half of the semester > >streamlining our spectroscopic observing and reduction procedure, so by > >mid-November we should be able to take some good spectra of it if you > >want to. These would be echelle spectra from ~ 4500 - 7000 Angstroms, R > >~ 10,000. > > > >And having a V magnitude of ~ 2 certainly helps! Though I couldn't tell > >you at this point what our S/N vs. time will look like. Do you have any > >sense of what timescales are of interest? > > > >Eric > > > > > >On Sep 9, 2011, at 2:26 PM, David Cohen wrote: > > >> >> Marc, >> >> >> >> This is exciting. I wonder if there'd be any utility to obtaining >> >>(near) simultaneous optical data with the Swarthmore telescope >> >>(photometric or, if we get our act together, spectroscopic). The star >> >>shows all kinds of variability, right? >> >> >> >> At the very least, it'll be fun to look up at Orion in November when >> >>the observations are being made. >> >> >> >> David >> >> >> >> >> >> On 9/9/11 2:23 PM, Gagne, Marc wrote: >>> >>> Maurice, David, >>> >>> >>> >>> Here are the Chandra LTS entries for zeta Ori. >>> >>> >>> >>> Segment: 60 limit: 3.85d, used 3.82d = 99.22% 14-Nov-2011 00h >>> >>>to 21-Nov-2011 00h (UT) >>> >>> >>> >>> #Orbits: 2 Orbit Time: 426.16ks LTS Time: 330.00ks Bad Pitch: >>> >>>0.00ks ( 0.00%) Cold: 0.00ks P-Line: 10.00ks<75: 0.00ks (130 to >>> >>>150): 320.00ks (150 to 156): 0.00ks >>> >>> >>> >>> 200757 >>> >>>13460 >>> >>>Zeta Orionis 180.0 85.190 -1.943 55.5 141.6 ACIS-S 6 0 HETG >>> >>>Leutenegger GO 12 0 N P N N N N not approved >>> >>>13200314 >>> >>> 200757 >>> >>>13461 >>> >>>Zeta Orionis 120.0 85.190 -1.943 55.5 141.6 ACIS-S 6 0 HETG >>> >>>Leutenegger GO 12 0 N P N N N N not approved >>> >>>13200314 >>> >>> >>> >>> Attachments: ZetaOri_HalphaVar.pdf 27 bytes